Author: Alexandra W. Dretler

The textbook signs of infection are fever, a raised heart rate and feeling obviously unwell. In someone over eighty, those may never appear.

What appears instead is confusion, a fall, a sudden loss of appetite, or simply not being themselves. Families notice it first and are frequently told it is nothing. It often is not.

Why the presentation changes

Two things shift with age. The immune response that produces fever becomes blunted, so the temperature may barely move even during a significant infection. And the brain becomes more vulnerable to any physical stress, so illness anywhere in the body shows up as a change in thinking.

The result is that an infection which would produce a dramatic fever at thirty can produce nothing but quiet confusion at eighty-five.

The same infections, presenting differently

Infection	Typical in a younger adult	Often in an older adult
Pneumonia	Cough, fever, chest pain	Confusion, a fall, faster breathing, little cough
Urinary infection	Burning, urgency, frequency	Confusion, new incontinence, loss of appetite
Skin infection	Redness, pain, fever	Redness with little pain, and withdrawal
Any serious infection	High fever, obvious illness	Low or normal temperature, drowsiness, not eating

The signs families notice first

• New or worsening confusion, or being unusually withdrawn and quiet
• A fall, or new unsteadiness in someone who normally walks well
• Not eating or drinking, or refusing a favorite food
• New incontinence, or a sudden change in continence
• Sleeping far more than usual, or being hard to rouse
• Simply not being themselves, which is worth stating plainly to a clinician

That last one carries more weight than people expect. A family member saying that someone is not themselves is a recognized and useful clinical signal, and it should be said directly rather than hedged.

The urine test problem

Here is where a great deal goes wrong. Many older adults, particularly women and anyone with a catheter, have bacteria in their urine all the time without being infected. This is called asymptomatic bacteriuria, it is common, and it does not require treatment.

So a confused older person gets a urine test, bacteria are found, and the confusion is blamed on a urinary infection. Sometimes that is right. Often it is not, and two things follow: they receive antibiotics they do not need, and the real cause of the confusion is not looked for.

• Bacteria in the urine plus urinary symptoms usually does mean infection
• Bacteria in the urine with no urinary symptoms usually does not
• Confusion alone, with no urinary symptoms, is weak evidence for a urinary infection
• Treating bacteriuria that is not causing illness does not help and carries real cost
• Cloudy or strong-smelling urine is not by itself a reason for antibiotics

Those costs are not theoretical. Unnecessary antibiotics in older adults cause C. difficile, which is more dangerous in this age group than in any other, alongside drug interactions, kidney effects and resistant organisms that make the next real infection harder to treat.

Where these infections usually start

A small number of sites account for most serious infection in older adults, and each has something practical that reduces the risk.

• The chest. Pneumonia is the most common serious infection in this age group. Difficulty swallowing raises the risk, because small amounts of food or fluid reach the lungs
• The urinary tract. Genuine infection is common, particularly with a catheter. Our article on recurrent urinary tract infections covers what actually prevents it
• The skin. Thin skin tears easily, and pressure areas and leg ulcers are entry points. Cellulitis can spread with little pain to signal it
• The mouth. Poor dental health feeds infection elsewhere, including the chest and occasionally the heart valves
• Devices. Catheters, feeding tubes and lines all provide a route in, and each should be reviewed regularly for whether it is still needed

The single most effective preventive step is removing a urinary catheter that is no longer necessary. Catheters are frequently left in long after the reason for them has passed, and every additional day carries risk.

What genuinely needs urgent attention

None of the above is an argument for waiting. The point is to look properly rather than to assume, and some things need to be seen the same day.

• Confusion that came on over hours rather than weeks
• Breathing that is faster than usual, or new breathlessness
• A temperature above 100.4 degrees Fahrenheit, or below 96.8
• Not passing urine, or passing very little
• Drowsiness, or difficulty waking the person
• Any of the warning signs of sepsis, which in older adults may appear without a fever at all

Sudden confusion in an older adult is treated as a medical problem until proven otherwise. It is not a normal part of aging, and gradual memory change over months is a different thing entirely from a change over a day or two.

What helps in advance

• Know the person’s usual baseline temperature, so a change is recognizable
• Keep a current list of medications and conditions somewhere findable
• Keep vaccinations current; see our article on adult vaccines
• Encourage fluids routinely, as thirst diminishes with age
• Keep dental and skin care up, since both are common entry points
• Write down what changed and when, before the appointment

If infections keep recurring, or a diagnosis has never been clear, our article on when to see an infectious disease specialist explains what that assessment adds. You can reach us through the contact page.

Frequently asked questions

It comes on fast. You were fine at lunch and by evening you cannot keep water down. The first question everyone asks is what they ate.

Often that is the wrong question. Sudden vomiting and diarrhea are far more often a virus passed from another person than anything wrong with a meal, and the difference matters, because one of them spreads through your household and the other does not.

The timing tells you more than the meal does

People reliably blame the last thing they ate. That instinct is usually wrong, because almost nothing causes illness within an hour or two, and the meal that made you sick is more often the one from the day before.

What the interval between eating and symptoms suggests

Onset after eating	Usually	Typical picture
1 to 6 hours	A toxin already present in the food	Violent vomiting, little fever, over within a day
12 to 48 hours	Norovirus, usually from a person not the food	Vomiting and watery diarrhea, aching, low fever
1 to 3 days	Bacterial infection such as salmonella	Diarrhea, cramps, fever, sometimes blood
3 to 7 days	Campylobacter, or other bacteria	Cramping diarrhea, fever, often after poultry
Over a week	Parasites, or something unrelated	Prolonged loose stool, weight loss

The middle row is the common one. Norovirus is the most frequent cause of sudden vomiting and diarrhea in adults, and while it can be carried on food, it is usually caught from another person or a surface they touched.

None of these intervals is exact, and they overlap. They are a guide to which explanation is more likely, not a way to identify an organism, and the only way to be certain is testing where testing is warranted.

Why norovirus spreads so efficiently

Norovirus is unusually good at what it does, and understanding why explains the precautions that actually work.

• It takes very few virus particles to infect someone
• It survives on surfaces for days
• It is shed before symptoms start and for at least two days after they stop
• Alcohol hand gel works poorly against it, unlike most other things
• Vomiting spreads it through the air onto nearby surfaces
• Having had it gives only short-lived protection, so you can catch it again

For the household, that means cleaning bathroom surfaces and door handles with a bleach-based product rather than a general spray, washing soiled laundry separately on a hot cycle, and keeping the unwell person away from food preparation until two days after they are better.

When the food really was the problem

Genuine food-borne infection tends to declare itself a day or more after the meal, often with more fever and more cramping. Poultry, undercooked ground meat, unpasteurized milk and cheese, raw shellfish, and pre-cut fruit and salad account for a large share.

If several people who shared a meal are ill and others who did not are well, the food is the likelier explanation. If the illness is moving through a household or an office over several days, it is almost certainly being passed person to person.

What to do while it runs its course

Most of these illnesses resolve on their own in one to three days and need no treatment. Dehydration is the actual risk, and it is the thing to manage.

1. Sip small amounts often rather than drinking a glass at once
2. Use oral rehydration solution if diarrhea is heavy, or if you are older or frail
3. Return to bland food as soon as you can face it; do not starve yourself
4. Skip alcohol and caffeine while symptoms last
5. Avoid anti-diarrheal medication if you have fever or blood in the stool
6. Stay off work, and away from cooking for others, for two days after symptoms stop

Antibiotics do not help viral illness and are usually unnecessary even for bacterial food poisoning, where they can prolong carriage of the organism. Our article on antibiotic resistance covers why that matters, and taking a course also raises the risk of C. difficile afterwards.

The four things that prevent most of it

Food safety advice tends to arrive as a long list nobody remembers. In practice most household food-borne illness comes down to four habits.

1. Separate. Raw meat, poultry and seafood are kept away from anything eaten raw. Cross-contamination in the kitchen causes more illness than undercooking
2. Cook. Use a thermometer rather than judging by color. Ground meat and poultry are the two where this genuinely matters
3. Chill. Refrigerate leftovers within two hours, or one hour in hot weather. Bacteria multiply fastest between refrigerator and cooking temperature
4. Clean. Wash hands, boards and counters between tasks, and replace sponges and cloths often, since they hold more bacteria than anything else in a kitchen

Some foods carry enough risk that certain people are advised to avoid them entirely: unpasteurized milk and soft cheese, raw or undercooked eggs, raw shellfish, raw sprouts, and deli meats that have not been reheated. That applies particularly during pregnancy, after sixty-five, and to anyone with suppressed immunity, including during cancer treatment.

When it stops being self-limiting

• Signs of dehydration: passing little urine, dizziness on standing, a dry mouth
• Blood in the stool, or black stool
• Fever above 102 degrees Fahrenheit, or fever lasting beyond a couple of days
• Vomiting that prevents any fluid staying down for more than a few hours
• Diarrhea lasting more than a week
• Severe abdominal pain rather than cramping that eases after passing stool
• Recent travel abroad, recent antibiotics, pregnancy, or a suppressed immune system

Frequently asked questions

Mono announces itself as a severe sore throat with swollen glands and a fever, and that part behaves much like any other bad throat infection. It settles within a couple of weeks.

The exhaustion does not. Weeks after the throat is fine, people are still sleeping ten hours and unable to get through a normal day. That gap between recovery and feeling recovered is the part nobody warns about.

What it is

Mononucleosis is usually caused by Epstein-Barr virus, a herpes-family virus that most people meet at some point. Caught in early childhood it usually passes as an unremarkable illness. Caught in adolescence or adulthood it produces the full picture.

It spreads through saliva, which is where the nickname comes from, though sharing drinks, utensils and toothbrushes does it just as effectively as kissing. The incubation period is long — four to six weeks — so tracing where you caught it is usually futile.

Why the tiredness lasts

The fatigue of mono is not ordinary tiredness and it does not respond to willpower. The immune response is doing something unusual and metabolically expensive, and the exhaustion tracks that response rather than the sore throat.

What settles when, roughly

Symptom	Usual course
Fever	One to two weeks
Sore throat	One to two weeks, worst in the first week
Swollen glands	Two to four weeks
Enlarged spleen	Four to six weeks, sometimes longer
Fatigue	Several weeks; a minority carry it for months

Pushing through does not shorten it and reliably makes it worse. The pattern people describe most often is a good day, followed by doing far too much, followed by two bad days. Recovery goes faster when the good days are not spent all at once.

The spleen is the part that matters

The spleen enlarges in a majority of cases. While enlarged it sits lower and is less protected by the ribs, and a blow to the abdomen can rupture it. That is rare, but it is a genuine emergency.

This is why contact sports, heavy lifting and vigorous exercise are avoided for at least three to four weeks, and longer for collision sports. The restriction is not about fatigue; it is about the spleen, and it applies even on days you feel well.

The rest of the body is involved too

Mono is often described as a throat illness, which undersells it. Epstein-Barr virus produces a whole-body response, and several of its other effects explain symptoms people find alarming because nobody mentioned them.

• The liver. Mild inflammation is common and shows on blood tests. It usually causes no symptoms and settles on its own, but it is the reason alcohol is discouraged for a few weeks
• Jaundice. A minority develop yellowing of the eyes or skin. It is worth reporting, though it usually resolves without treatment
• Swollen glands. Nodes in the neck can stay enlarged for weeks after everything else has settled, which is normal rather than sinister
• A puffy face or eyelids. Common early, and often the first thing family members notice
• Rash. Can occur without any antibiotic being involved at all

None of these means the illness is going badly. They are part of the ordinary picture, and knowing that in advance saves a great deal of worry during a recovery that is already longer than expected.

Diagnosis, and one thing to avoid

Diagnosis is usually a blood test, alongside a count showing the characteristic changes in white cells. Tests done very early can be negative and may need repeating.

There is one classic trap. Mono is easily mistaken for bacterial tonsillitis, and if amoxicillin or ampicillin is given, most people with mono develop a widespread rash. It is not a true drug allergy, but it is frequently recorded as one, and that label then follows them for life. Our article on penicillin allergy labels covers the cost of carrying one wrongly.

Going back to work or school

There is no fixed exclusion period. Mono is not spread by being in the same room, and people are not kept away from work or school on infection-control grounds. The limit is what you can actually manage.

Most people return part-time before they return fully, and the ones who do best treat the first fortnight back as a phased return rather than a finish line. Students often need adjustments for deadlines or exams, and a note from a clinician is worth asking for early rather than once something has already been missed.

Set expectations with the people around you as well. Mono has a reputation as a mild illness because the name sounds unserious, and colleagues, teachers and family frequently underestimate it. Being explicit that the fatigue runs for weeks, and is not a matter of effort, prevents a lot of unhelpful pressure.

What actually helps

• Rest, without treating it as optional; the fatigue is physiological
• Fluids, in quantity, especially while swallowing is painful
• Acetaminophen or ibuprofen for throat pain and fever
• Cold drinks, ice, and soft food while the throat is at its worst
• Avoiding alcohol for a month or so, since the liver is often mildly inflamed
• Returning to activity gradually, in steps rather than all at once

Antibiotics do nothing, because this is a virus. Antiviral drugs are not used for ordinary mono either. Our article on antibiotic resistance explains why taking them anyway carries a real cost.

When to be seen

• Difficulty breathing, or a throat so swollen that swallowing fluids fails
• Inability to keep fluids down, or signs of dehydration
• Severe abdominal pain, particularly upper left
• Yellowing of the eyes or skin
• Fatigue that is not improving at all after several weeks, which is worth reassessing rather than assuming — see our article on a fever that will not go away

Frequently asked questions

Syphilis was close to eliminated in the United States twenty five years ago. It is now rising steeply, including among people who would never consider themselves at risk.

It is also entirely curable, usually with a single injection, and detected by an ordinary blood test. The gap between how treatable it is and how often it is missed is the whole problem.

Why it goes undetected

The first sign of syphilis is a sore called a chancre. It has three properties that together make it very easy to miss.

• It is painless, so nothing prompts you to look
• It is often hidden — inside the vagina, the anus, the mouth, or under foreskin — where it is never seen
• It heals by itself in three to six weeks whether or not it is treated

That last point is the dangerous one. The sore going away feels like the problem resolving. It is not. The infection continues, and the next stage may not appear for weeks or months.

The stages, and what they look like

How syphilis progresses when untreated

Stage	When	What is seen
Primary	3 weeks after exposure, roughly	A single painless sore, often unnoticed
Secondary	Weeks to months later	Rash, often on the palms and soles; fever; swollen glands; hair loss
Latent	After symptoms settle	Nothing at all; detectable only by blood test
Late	Years later, in a minority	Damage to the heart, brain, nerves or eyes
Neurological or eye involvement	Any stage	Headache, vision or hearing change, confusion

The rash of secondary syphilis is the one detail worth remembering, because it is unusual. Rashes on the palms of the hands and soles of the feet are uncommon in general, and this is one of the few conditions that regularly causes them.

Who should be tested

Because the latent stage produces no symptoms whatever, testing is the only route to finding it. It is a blood test, it is inexpensive, and it is routinely offered alongside other screening.

• Anyone with a new partner, or more than one partner
• Everyone who is pregnant, at the first visit — and again later where risk exists
• Anyone diagnosed with another sexually transmitted infection
• Anyone taking PrEP for HIV prevention, as part of routine review
• Anyone with an unexplained rash involving the palms or soles
• Anyone whose partner has been diagnosed

Why there are two blood tests, not one

Syphilis testing routinely involves two different blood tests, and understanding why prevents a good deal of confusion when results are explained.

One type detects antibodies to the organism itself. Once positive, it generally stays positive for life, treated or not. It answers the question of whether you have ever had syphilis, and it cannot tell you whether the infection is active now.

The other type measures a marker that rises with active infection and falls after successful treatment. It is reported as a number, and that number is what follow-up tracks. A falling result confirms treatment worked; a rising one suggests reinfection or treatment failure.

• A permanently positive test does not mean you are still infected
• The numerical result is the one that matters after treatment
• Keep a record of your result and its number, because future testing is interpreted against it
• A previously treated infection makes later results harder to read without that history, which is why the record is worth holding onto

Testing in pregnancy is the urgent case

Congenital syphilis, where the infection passes to a baby during pregnancy, has risen faster than syphilis overall. It can cause stillbirth, prematurity and lasting harm.

Almost all of it is preventable. Testing at the first prenatal visit, repeated later where there is ongoing risk, catches it in time for treatment that protects the baby. Our article on infections and vaccines in pregnancy covers what else is screened for.

Treatment is simpler than people expect

Syphilis has never developed resistance to penicillin. Early infection is treated with one injection of a long-acting form; later or latent infection needs three weekly injections. Treatment stops the infection and prevents further damage.

Damage already done is not reversed, which is the argument for testing rather than waiting for symptoms.

If you carry a penicillin allergy label, raise it early. Penicillin is so clearly the best treatment here, and the only one recommended in pregnancy, that formal assessment of the label is worthwhile rather than simply accepting a second choice. Our article on whether a penicillin allergy label is accurate explains why most turn out to be wrong.

After treatment

• Follow-up blood tests confirm the infection is responding; they are part of the cure
• Avoid sex until treatment is complete and you have been told it is safe
• Partners need testing and usually treatment, even if they feel entirely well
• Being treated once does not protect you; reinfection is common
• Testing for other infections is offered at the same time, because they travel together

Frequently asked questions

If you are arranging testing or have had a positive result, our article on when to see an infectious disease specialist explains what the appointment covers.

A positive hepatitis B test is not a single diagnosis. It is a panel of several results read together, and the combination decides everything that follows.

Some people are told they are immune. Some are told they had it years ago and cleared it. Some are told they carry it chronically. Those are very different situations, and they are all reported from the same set of blood tests.

Why the panel confuses people

Three results do most of the work. One indicates current infection, one indicates immunity, and one indicates past exposure. Reading them together tells you which of four quite different situations you are in.

What the common combinations usually mean

Picture	What it means	What follows
Surface antigen positive	Current infection, acute or chronic	Further tests to see which, then monitoring
Surface antibody positive alone	Immune from vaccination	Nothing; you are protected
Surface antibody and core antibody positive	Past infection, now cleared	Usually nothing further
Core antibody positive alone	Past exposure, needs interpretation	Matters before immune-suppressing treatment
All negative	No infection and no immunity	Vaccination is worth discussing

That fourth row is the one most often misread. Core antibody alone is not a diagnosis of active infection, but it is not nothing either, and it becomes important if you are ever given treatment that suppresses the immune system.

Who gets tested, and why it is often incidental

Most people who learn they have hepatitis B were not looking for it. It turns up on screening before surgery, during pregnancy, at a blood donation, on an immigration medical, or before starting a medication that suppresses the immune system.

That is not an accident of testing practice. Chronic hepatitis B usually causes no symptoms for decades, which is precisely why screening exists rather than waiting for people to feel unwell.

• Anyone born in a region where hepatitis B is common, which includes much of Asia, Africa, the Pacific and parts of Eastern Europe
• Anyone whose parent was born in one of those regions, because transmission at birth is the usual route
• Household members and sexual partners of anyone infected
• Anyone about to start chemotherapy, a biologic, or long-term steroids
• People on dialysis, and people with HIV or hepatitis C
• Anyone with persistently abnormal liver blood tests and no explanation

Screening is now recommended at least once for all adults, which is a broader position than the risk-based approach many people remember.

Acute and chronic are different diseases

Acute hepatitis B is the illness that follows soon after infection. It can cause jaundice, nausea and profound fatigue, or it can pass unnoticed. In adults who catch it, the great majority clear the virus on their own and become immune.

Chronic hepatitis B means the virus is still present six months later. The risk of that outcome depends enormously on the age at which infection happened. Infection in infancy usually becomes chronic; infection in adulthood usually does not.

This is why most people living with chronic hepatitis B worldwide acquired it at birth or in early childhood, often without anyone knowing, and are diagnosed decades later on a routine test.

Chronic does not mean the same thing for everyone

Chronic infection is not one steady state. It moves through phases, and the phase you are in decides whether treatment is needed now, later, or possibly never.

• Some people have virus present but no liver inflammation and normal blood tests
• Some have active inflammation, which is what damages the liver over time
• Phases can change, in both directions, over years
• Treatment is aimed at people in an active phase, not at everyone who tests positive
• Not being on treatment is a monitoring decision, not a gap in your care

What monitoring involves

For most people this is straightforward and does not disrupt life. Blood tests check liver enzymes and the amount of virus present. Where risk factors warrant it, an ultrasound is added to screen for liver cancer, because chronic hepatitis B raises that risk even when the liver is not scarred.

That screening is the single strongest argument for staying in follow-up. Liver cancer found on a scheduled scan is a far more treatable problem than liver cancer found because symptoms appeared.

Treatment, when it is needed

Where treatment is indicated it is usually one tablet daily, well tolerated, and taken long term. It suppresses the virus, allows the liver to recover, and substantially reduces the risk of cirrhosis and cancer.

It is not a cure in the way that hepatitis C treatment is. Hepatitis C is now cured with a short course of tablets; hepatitis B is controlled rather than eliminated. Confusing the two is common and leads to real disappointment, so it is worth being clear which one you have.

Protecting people around you

Hepatitis B spreads through blood and body fluids, not through casual contact. You cannot pass it by sharing food, cooking, hugging, coughing or using the same bathroom.

• Household members and sexual partners should be tested and vaccinated
• The vaccine is highly effective and is part of the routine adult schedule, covered in our article on adult vaccines
• Do not share razors, toothbrushes or nail clippers
• Cover cuts, and clean blood spills with diluted household bleach
• Tell any clinician doing a procedure, so nothing is missed
• In pregnancy, treatment and infant vaccination prevent transmission at birth; see our article on infections and vaccines in pregnancy

One more point worth raising with any doctor who prescribes for you. If you have evidence of past or current hepatitis B and are given chemotherapy, a transplant, steroids or a biologic, the virus can reactivate. Preventive treatment is given alongside. The same conversation usually covers latent tuberculosis screening.

Frequently asked questions

If you are working out what a result means or whether you need follow-up, our article on when to see an infectious disease specialist explains what that appointment covers. You can reach us through the contact page.

Childhood vaccination is organized, scheduled and chased up. Adult vaccination is largely left to the individual to remember, and most people have no idea what they are due or when they last had anything.

The adult schedule is genuinely useful, and it is shorter than people expect. It is built around a small standing list, a few things that change with age, and a set of additions that depend on health conditions rather than on birthdays.

How the adult schedule is organized

Rather than memorizing a list, it helps to see the four reasons an adult vaccine is recommended. Almost everything fits one of them.

Why any given adult vaccine is recommended

Reason	What it covers	Example
Every year	Protection that does not last	Influenza, each fall
Periodic booster	Protection that fades over years	Tetanus and diphtheria, every ten years
Age threshold	Risk that rises with age	Shingles and pneumococcal vaccines
Health condition or exposure	Risk from a condition, job or travel	Hepatitis B, and travel vaccines

One caution before any specifics. Adult recommendations are reviewed and changed regularly, and the age thresholds in particular have moved more than once in recent years. Treat what follows as the shape of the schedule rather than the final word, and confirm the current detail against the schedule linked at the end of this article or with your own clinician.

The annual one

Influenza vaccine is recommended every year for essentially all adults. It is annual for two separate reasons: the circulating strains change, and the protection itself fades over a season.

Timing matters more than people realize. Fall, before influenza is circulating widely, is the target. It takes about two weeks to take effect, and getting it in December after an outbreak has started gives away much of the benefit. Higher-dose formulations are available for older adults, whose response to the standard version is weaker.

The one most adults are overdue for

Tetanus, diphtheria and pertussis protection needs a booster every ten years, and this is the vaccine adults are most commonly behind on. Many people last had it in childhood.

The pertussis component is the part that has changed. At least one adult booster should include it, because whooping cough remains in circulation and adults with a mild, lingering cough are a common source of infection in infants who are too young to be protected themselves.

It is also the vaccine most likely to be needed at short notice, since a dirty wound or a bite requires a booster if it has been more than five years. Our article on bites and infection risk covers that shorter interval.

In pregnancy, a pertussis-containing booster is recommended in every pregnancy, timed to pass protection to the baby. Our article on infections and vaccines in pregnancy covers the detail.

What changes as you get older

• Shingles. Recommended from age fifty, given as two doses. Also recommended for younger adults with suppressed immunity. Our article on shingles, its pain and the vaccine explains why it matters beyond the rash
• Pneumococcal. Recommended at an age threshold that has been lowered in recent years, and earlier for adults with chronic heart, lung, liver or kidney disease, diabetes, no spleen, or suppressed immunity. Relevant to anyone who has had pneumonia
• RSV. Recommended for older adults, with a lower age threshold for those with chronic conditions
• COVID-19. Recommendations are updated each season and are now largely organized around age and risk rather than applying uniformly

The ones that depend on you, not your age

A second group is recommended because of a health condition, a job, a living situation or travel, and these are the ones most often missed because nothing prompts them.

• Hepatitis B — now recommended for all adults through middle age, and beyond that for anyone with diabetes, kidney disease, liver disease or specific risk factors
• Hepatitis A — for liver disease, certain exposures and some travel
• HPV — routine through the mid twenties, and a discussion worth having up to the mid forties
• Meningococcal — for people without a spleen, certain immune conditions, some students and some travel
• MMR and varicella — for adults with no evidence of immunity, though these are live vaccines and not given during pregnancy or with significant immune suppression
• Travel vaccines — covered in our article on how far in advance to book travel vaccines

If you take an immune-suppressing medication, or are being assessed for one, raise vaccination before starting rather than after. Live vaccines are generally avoided once immunity is suppressed, and the response to inactivated vaccines is better beforehand. The same conversation usually covers screening for latent tuberculosis.

Finding out what you have already had

Almost nobody knows their full history, and the records are more findable than people assume. Georgia maintains a statewide immunization registry, and pharmacies keep records of everything they administer.

• Ask your primary care office to check the state immunization registry
• Ask any pharmacy where you have had a flu shot; they hold their own records
• Employers, universities and the military often hold records for required vaccines
• Blood testing can confirm immunity to hepatitis B, measles and chickenpox where records cannot be found
• Where nothing can be established, it is safe to vaccinate rather than assume

Once you have assembled it, keep a copy yourself. It is asked for on travel, before surgery, when starting immune-suppressing treatment, and at every new registration.

Where to get them

Most routine adult vaccines are available at pharmacies without an appointment, and most are covered by insurance as preventive care. Vaccines tied to a specific condition are usually better arranged through the clinician managing that condition, who can sequence them around treatment.

For travel, timing is the constraint rather than availability, and some schedules need weeks. Our travel medicine service handles that, and the practice page explains what else we cover.

Frequently asked questions

A dog bite that tears the skin looks alarming and gets attention immediately. A cat bite leaves two small punctures that stop bleeding in a minute and look like nothing at all.

The cat bite is the one far more likely to become infected. Understanding why explains most of what matters about bite wounds, and it is the opposite of what the appearance suggests.

Why bites infect so readily

A bite is not a clean cut. It is an injection of mouth bacteria into tissue, delivered by teeth designed to puncture. The mouths of cats, dogs and humans all carry dense mixed populations of bacteria, and a bite deposits them below the skin where the immune system has more difficulty reaching them.

The shape of the wound then decides what happens next. A wide laceration bleeds freely, washes itself out to some degree and can be cleaned thoroughly. A narrow puncture seals over within hours, trapping bacteria in a warm pocket with damaged tissue and no drainage. Cats have long, fine teeth, so they produce exactly the second kind.

How the common bite types compare

Bite	Typical wound	Infection risk	Particular concern
Cat	Deep, narrow punctures	High, often around half	Reaches joints and tendon sheaths easily
Dog	Crushing and tearing	Lower, roughly one in five	Tissue damage; force injuries in children
Human	Puncture or laceration	High	Knuckle wounds from a punch are the worst kind
Rodent or rabbit	Small puncture	Low	Rarely needs antibiotics
Wild mammal	Variable	Variable	Rabies assessment comes first

The first hour

What happens in the first hour has more influence on whether a bite becomes infected than anything prescribed later. The main intervention is unglamorous: water, and a lot of it.

1. Let it bleed briefly. Bleeding flushes the wound; do not rush to stop it
2. Wash under running water for a full five minutes, longer than feels necessary
3. Use soap around the wound; irrigate the wound itself thoroughly with water
4. Apply pressure with a clean cloth if bleeding continues
5. Cover with a clean dry dressing, but do not tape a puncture wound tightly closed
6. Raise the area above heart level, which limits swelling considerably
7. Write down the time of the bite, and what bit you

Cat bites, and the hand

Cat bites are the highest risk of the common ones, and cat bites to the hand are higher still. The hand has very little soft tissue between skin and the structures beneath, so a puncture that looks superficial can seed a joint or a tendon sheath directly.

A tendon sheath infection is a surgical problem, not an antibiotic problem, and it can cost permanent function if it is left. The warning combination is a finger that is swollen along its whole length, held slightly bent, painful to straighten, and tender along the tendon rather than just at the puncture.

Human bites, and the injury nobody reports

Human bites carry an infection risk comparable to cat bites. The most important is not a bite in the ordinary sense at all: it is the wound made when a closed fist strikes someone in the mouth and a tooth splits the skin over a knuckle.

That injury reaches the joint capsule almost by definition. When the hand relaxes afterwards, the tendon carries contamination back inside and the small skin wound closes over it. It is very often presented late, and sometimes described as something else, which is exactly why it goes wrong.

Any wound over a knuckle following a punch needs same-day assessment. Saying plainly how it happened changes the treatment; a knuckle wound described as catching the hand on a door frame does not get the attention it needs.

In the clinic

Assessment covers the wound, what is underneath it, and two questions that have nothing to do with bacteria: tetanus and rabies.

• Irrigation and exploration. The wound is cleaned properly and checked for damage to tendon, nerve or joint, and for a retained tooth fragment
• Closure. Many bites, especially punctures and hand wounds, are left open on purpose; closing them raises infection risk
• Tetanus. A booster is given if it has been more than five years, which is a shorter interval than the usual ten for a dirty wound
• Rabies. Assessed for bats and wild mammals, and for domestic animals whose vaccination status is unknown or that cannot be observed
• Antibiotics. Prophylaxis is usual for cat bites, human bites, hand and face wounds, deep punctures, and anyone with reduced immunity

The standard choice covers the mixed mouth bacteria involved, and it is a penicillin-class combination. If you carry a penicillin allergy label, say so early, and read our article on whether that label is accurate — the alternatives for bite wounds are noticeably less good, and most labels turn out to be wrong.

People without a functioning spleen, on immune-suppressing treatment, or with poorly controlled diabetes are treated more cautiously across the board. A dog bite in someone without a spleen is a specific and urgent situation.

When to be seen, and how quickly

• Any cat bite, particularly to the hand, and any bite over a joint
• Any wound over a knuckle after a punch
• A bite from a bat, or any wild or unfamiliar animal
• Bites to the face, hand, foot or genitals
• Any bite in someone with diabetes, no spleen, or suppressed immunity
• Deep wounds, wounds you cannot clean, or wounds that will not stop bleeding

Return the same day if redness spreads, pain increases after the first day, the area becomes hot and swollen, fluid or pus appears, you develop fever, or you cannot move the part normally. Spreading redness after a bite is cellulitis, and treated bites can still become infected.

Frequently asked questions

For wounds that are slow to heal after the initial infection has settled, our article on why some wounds do not heal covers what gets in the way. You can reach the practice through the contact page.

Say fungal infection and most people picture athletes foot or a thickened toenail. That is the overwhelming majority, it is a nuisance rather than a danger, and it is treated from a pharmacy shelf or a short prescription.

A much smaller group of fungal infections behaves nothing like that. They reach the lungs, the bloodstream or deeper tissue, they are treated for months rather than weeks, and they occur mainly in people whose immune defenses are down. Telling the two apart is the useful thing to understand.

Fungi are everywhere, and mostly harmless

Fungi are their own kingdom of life, separate from bacteria and viruses. They live in soil, on decaying plant matter, in dust and on our own skin and mucous membranes. You inhale fungal spores constantly and it does not matter.

That is the key to the whole subject. Exposure is universal; disease is not. What determines whether a fungus causes an infection is far more about the state of the person than the presence of the fungus.

Two very different categories

Superficial and invasive fungal infections compared

	Superficial	Invasive
Where	Skin, nails, hair, mouth, vagina	Lungs, blood, brain, deep organs
Who gets it	Anyone	Mostly people with suppressed immunity
How common	Very	Uncommon
Typical treatment	Cream, or tablets for a few weeks	Tablets or infusions, months
Seen by	Primary care or dermatology	Infectious disease, often with other specialists
Serious?	Rarely	Yes

Thrush sits between the two. Oral or vaginal candida is common and easily treated in healthy people, but oral thrush appearing in an adult with no obvious cause is worth mentioning, because it occasionally points to something suppressing immunity that has not yet been identified.

Where the serious ones come from

Some fungi are geographic. They live in the soil of particular regions, and infection follows disturbing that soil rather than contact with another person. None of these spread from person to person.

• Histoplasma — soil enriched by bird or bat droppings, common through the Ohio and Mississippi River valleys and present in the Southeast
• Blastomyces — damp soil and rotting wood, overlapping regions
• Coccidioides, which causes Valley fever — dry soil of the Southwest and parts of California, and a common reason for illness after travel there
• Cryptococcus — soil and bird droppings worldwide, mainly a problem in people with suppressed immunity
• Aspergillus — ubiquitous mold in dust, compost and construction sites, inhaled by everyone and dangerous to few

Most people who inhale these clear them without ever knowing. Histoplasma exposure in particular is so common in endemic areas that many residents have evidence of past infection and were never ill. Where it does cause disease, it often looks like a pneumonia that will not resolve, or like a fever with no obvious source.

The one most likely to matter in Georgia

Of that list, histoplasmosis is the one with the clearest local relevance. The organism is established across the Southeast, and the activities that stir it up are ordinary ones: clearing an old barn or shed, cutting down a tree, cleaning a chicken coop, disturbing an attic or a chimney where birds or bats have roosted, or working on a demolition site.

In a healthy adult, the usual result of that exposure is either nothing at all or a flu-like illness for a week or two that never gets a name. Only a minority develop a pneumonia that lingers, and fewer still develop disease that spreads beyond the lungs.

The reason it is worth knowing about is diagnostic rather than preventive. Someone presenting with weeks of fever, cough and fatigue after a weekend clearing an old building is a recognizable picture, but only if the exposure is mentioned. It rarely comes up unless the patient thinks to raise it, which is exactly why it belongs in the history you prepare.

Who actually gets invasive infection

• People having chemotherapy, particularly with low white cell counts, as covered in our article on infections during cancer treatment
• Organ and stem cell transplant recipients on anti-rejection drugs
• People on long-term steroids or TNF inhibitors
• People with advanced or untreated HIV
• Patients in intensive care with central lines and long antibiotic courses
• People with structural lung disease such as emphysema or old cavities
• People with poorly controlled diabetes, for certain specific infections

Why diagnosis takes time

Fungi grow slowly. A bacterial culture often declares itself within a day or two; a fungal culture can take weeks, and treatment frequently has to begin before it is confirmed.

To bridge that gap, other tests are used: antigen tests on blood or urine, antibody tests, and imaging patterns that suggest fungal disease. Each is helpful and none is perfect, which is why several are usually combined. A biopsy is sometimes the only way to settle it.

Treatment, and why it runs long

Superficial infections respond to topical treatment or a short course of tablets. Nail infections are the slow exception, needing months simply because the nail has to grow out.

Invasive infections are treated for months, sometimes a year, and often begin with intravenous therapy before switching to tablets. Where that continues at home, our article on outpatient IV antibiotics describes how it works in practice.

Two things make antifungal treatment distinctive. Drug interactions are extensive, because the azole antifungals affect the same liver pathway as many common drugs, including statins and some heart medications. And blood levels of the drug are often measured, which is unusual in ordinary antibiotic treatment but routine here.

Frequently asked questions

If a fungal infection has been raised and you are unsure how serious it is, our article on when to see an infectious disease specialist explains what the assessment covers.

Most fevers explain themselves within a few days. You get a sore throat, a cough or a stomach upset, the fever tracks alongside it, and both settle.

Occasionally a fever arrives without any of that, and then does not leave. Weeks pass, the first round of tests comes back normal, and nobody can yet say why. That situation has a name, a defined approach, and a better outlook than it feels like from inside.

What counts as a prolonged fever

Clinicians use a specific definition rather than a vague one, because it decides when the search changes gear. A fever of unknown origin means a temperature above about 101 degrees Fahrenheit on several separate occasions, lasting more than three weeks, with no diagnosis after an initial round of sensible investigation.

All three parts matter. Three weeks rules out the ordinary viral illnesses that account for most fevers. Several occasions rules out a single misleading reading. And “after initial investigation” means the straightforward explanations have already been looked for and not found.

What it usually turns out to be

The causes fall into a small number of groups, and the proportions have shifted over the decades as imaging and testing improved. Infections were once the overwhelming majority; they are now roughly a quarter.

The categories a prolonged fever is worked through

Category	Examples	Roughly how often
Infection	Abscess, endocarditis, tuberculosis, bone infection	About a quarter
Inflammatory conditions	Vasculitis, adult Still disease, connective tissue disease	About a fifth
Cancer	Lymphoma, leukemia, kidney cancer	Roughly one in six
Medications	Drug fever, which resolves on stopping the drug	Under one in ten, and often missed
No cause found	Settles on its own without a diagnosis	A third or more

That last row is the one worth holding onto. In modern series, a substantial share of prolonged fevers never receive a label and resolve anyway. An undiagnosed fever that is settling is a good outcome, not an incomplete one.

The history does more work than the tests

This is the part patients tend to underestimate. In prolonged fever, the detail that cracks it is usually something the patient knows and has not been asked. It is worth preparing before the appointment rather than trying to recall it in the room.

• Every country you have traveled to, and when, however long ago
• Animals: pets, bites, tick exposure, farm or bird contact
• Your work, and anything you are exposed to there
• Every medication, including supplements, and exactly when each was started
• Recent dental work, surgery, or any implanted device or prosthetic joint
• Anyone at home or at work with tuberculosis, or a positive test in the past, as covered in our article on latent tuberculosis
• Unpasteurized milk or cheese, undercooked meat, or well water
• Family history of periodic fever or autoimmune disease

The medication list deserves particular attention. Drug fever can begin days or weeks after a drug is started, produces no rash in most cases, and looks exactly like an infection. It is diagnosed by stopping the suspect drug and watching, and it is the most reversible cause on the list.

How the investigation proceeds

The workup is deliberately staged. Tests are not ordered all at once, because a scattergun approach produces incidental findings that send the search sideways.

1. Repeat the basics: blood counts, inflammatory markers, liver and kidney function, urine testing
2. Blood cultures, ideally several sets taken before any antibiotic is given
3. Targeted tests based on the history, not a standard panel
4. Cross-sectional imaging of the chest, abdomen and pelvis
5. Echocardiography if a heart valve infection is plausible
6. Specialized imaging or biopsy of anything the earlier steps flagged

Imaging, and its limits

Imaging finds abscesses, enlarged lymph nodes and tumors that explain a fever. It also finds a great many things that are present in healthy people and have nothing to do with the fever, which is why results are read alongside the history rather than on their own.

Where standard imaging is unrevealing and the fever persists, functional imaging such as a PET scan is sometimes used to point toward tissue worth sampling. It suggests where to look; it rarely gives the answer by itself.

What you can do while it is being worked out

• Take your temperature at the same times each day and write it down with the time
• Note anything alongside it: sweats, rash, joint pain, weight, appetite
• Weigh yourself weekly, because documented weight loss changes the assessment
• Photograph any rash when it appears, since rashes rarely last until the appointment
• Bring the full medication list, including anything started and stopped
• Use acetaminophen for comfort if advised, but record the temperature before you take it

When it stops being a waiting game

Prolonged fever is usually investigated at an outpatient pace. Some developments change that, and they are worth knowing in advance.

• Confusion, severe drowsiness, or difficulty rousing
• Breathlessness at rest, chest pain, or a fast heart rate that does not settle
• A new rash that does not fade under pressure
• A stiff neck with headache and light sensitivity
• Any of the warning signs of sepsis

Frequently asked questions

Our article on when to see an infectious disease specialist covers what that referral involves. You can reach us through the contact page.

You had a tuberculosis test because a job, a school, an immigration application or a new medication required it. The test came back positive. You feel completely well.

In almost every case, this means latent tuberculosis infection. It is not the same as tuberculosis disease, you are not infectious, and there is nothing you need to do tonight. It does need attention, and here is why.

What latent means

Tuberculosis bacteria are inhaled in small numbers, usually from prolonged close contact with someone who had untreated tuberculosis of the lungs. In most healthy people the immune system surrounds the bacteria and walls them off before they can cause illness.

The bacteria are not killed. They sit dormant inside those walled-off pockets, doing nothing, sometimes for the rest of a persons life. The immune system holds the line, and the only trace is that a test can now detect the immune response.

That is latent infection: organism present, disease absent. You have no symptoms, your chest X-ray is normal, and you cannot pass tuberculosis to anyone, including children and people living in your home.

Latent and active are different conditions

How latent infection differs from tuberculosis disease

	Latent infection	Active disease
Symptoms	None	Cough, fever, night sweats, weight loss
Chest X-ray	Normal	Usually abnormal
Contagious to others	No	Yes, if in the lungs or airway
Feels unwell	No	Usually, and often for weeks
Skin or blood test	Positive	Usually positive
Treatment	One or two drugs, three to four months	Four drugs, six months or longer
Urgency	Planned, over coming weeks	Immediate

The distinction matters because the tests cannot tell them apart. A positive skin or blood test is the beginning of the assessment, not the end of it. What separates the two is symptoms and a chest X-ray, which is why one is arranged before any treatment is offered.

The two tests, and why they disagree

There are two ways to test. The older is the skin test, where a small amount of protein is injected into the forearm and the raised area measured two to three days later. The newer is a blood test, which measures how your white cells respond to tuberculosis proteins in the tube.

The blood test has one clear advantage. If you were given BCG vaccine as a child, which is routine in much of the world and not in the United States, the skin test can read positive purely because of the vaccine. The blood test is not affected by BCG, so it answers the question the skin test leaves open.

• The skin test needs a second visit to be read; the blood test does not
• BCG vaccination can cause a false positive skin test, sometimes decades later
• Neither test distinguishes latent infection from active disease
• Neither test tells you when you were exposed
• A positive result does not become negative after treatment, so repeat testing is not used to check that treatment worked

Who is tested, and who should be

Testing is targeted rather than universal, because testing people at very low risk produces more false positives than real ones. Screening is aimed at people more likely to have been exposed, or more likely to become unwell if they were.

• People born in, or who lived in, countries where tuberculosis is common
• Close contacts of someone diagnosed with active tuberculosis
• Healthcare workers, and people who live or work in congregate settings
• Anyone about to start a TNF inhibitor or similar immune-suppressing biologic
• People with HIV, as covered in our article on HIV prevention and care
• People on dialysis, awaiting transplant, or on long-term steroids
• People having treatment for cancer that suppresses immunity

Why it is worth treating

Roughly five to ten percent of people with latent infection will develop active tuberculosis at some point, and most of that risk falls in the first two years after exposure. Ninety percent will never become unwell.

Those odds change sharply if immunity drops. Starting a TNF inhibitor for rheumatoid arthritis or inflammatory bowel disease, beginning chemotherapy, receiving a transplant, or having untreated HIV all raise reactivation risk substantially. This is why rheumatologists and transplant teams screen before starting these drugs rather than after.

Treating latent infection removes most of that future risk. It is the one point in the whole course of tuberculosis where a short, straightforward treatment prevents a long, difficult one.

What treatment involves

Treatment has become considerably shorter. The nine-month daily course many people have heard about is no longer the usual first choice. Current preferred regimens run three to four months, and shorter courses are completed far more often than long ones.

Regimens in common use for latent infection

Regimen	How long	How often
Isoniazid and rifapentine	3 months	Once weekly, 12 doses
Rifampin alone	4 months	Daily
Isoniazid and rifampin	3 months	Daily
Isoniazid alone	6 to 9 months	Daily

Which one you are offered depends on your other medications, your liver, whether you are or may become pregnant, and what the strain is likely to be sensitive to. Rifampin in particular interacts with a long list of drugs, including hormonal contraception and some HIV medications, so the full list of what you take matters.

Liver blood tests are checked at the start, and repeated during treatment if you have risk factors. Report nausea that does not settle, abdominal pain, dark urine or yellowing of the eyes rather than waiting for the next appointment.

Finishing it

The single thing that determines whether treatment protects you is finishing it. A partial course gives partial protection, and stopping early is the most common reason treatment fails to do its job.

Your positive test will stay positive afterwards. That is expected and is not a sign that treatment did not work. Ask for a written record of what you took and for how long, because you will be asked about that positive test again, and the record saves you repeating the whole assessment.

Frequently asked questions

If you are weighing up screening, treatment or a positive result from an occupational check, our article on when to see an infectious disease specialist explains what that appointment covers. Our practice information is on the our practice page.